How do I switch Apple IDs on iPhone without a 90-day hiatus for Music access?

I have 2 Apple IDs I use for my desktop Mac and iPhone for daily work and the other on my MB Air for entertainment and other, it has an Apple Music account and many music downloads. Why cannot I switch IDs so that I can use my iPhone which is on the work account to the other account when I am in the car to listen to music without incurring the 90 day hiatus?

[Re-Titled By Moderator]